Computer hackers breached North Korea's official media accounts on Saturday, mocking the youthful heir apparent to the country's leadership on his birthday.

A video was posted on the country's YouTube channel that depicted a caricature of Kim Jong Un driving a luxury sports car, running over women and children on the side of the road.

In a string of messages on the North's Twitter account, the hackers accused Kim Jong Il, the country's current leader and Kim Jong Un’s father, of extravagant spending on nuclear weapons and engaging in lavish drinking parties "while 3 million people are starving and freezing to death." Another tweet on the social media account called for an uprising to kill the Kims "with a sword."

It is not known who coordinated the cyber-attack. South Korean citizen media websites and the Yonhap news agency attributed the scheme to South Korean hackers.

It was the first birthday for the younger Kim - believed to be his 28th - since he debuted last September as his ailing father’s eventual successor.

The elder Kim’s birthday, on February 16, 1941, has been marked as a national holiday in the reclusive communist nation. He is extolled by the official state media as Dear Leader.

North Korea’s official state media did not report any celebratory events to mark the younger Kim’s birthday.

But Radio Pyongyang aired Let’s Raise a Toast, a song it has repeatedly played at various times in the past to note a celebratory mood in the country.